1. Field of the Invention:
This invention relates to a device for applying a constant force to a scoring wheel during the scoring of a glass sheet.
2. Discussion of the Prior Art and Technical Problems:
In the prior art there is taught the use of spiraled coiled springs for applying a force to a scoring wheel. Such teachings are found in U.S. Pat. Nos. 3,240,090; 3,280,676; 3,280,677; 3,577,636; 3,807,261 and 3,821,910 to name a few.
The drawback of spiraled coiled springs for applying a force to a scoring wheel is that the force of the spring is a function of the spring compression or extension.
For example, the spiraled coiled spring is adjusted to apply a predetermined force to a scoring wheel to score a glass sheet as it moves on conveyor rolls. Conveyor roll eccentricity and glass ribbon cross bow oscillates the scoring wheel relative to the conveyor rolls. In other words, the spiraled coiled spring expands to urge the scoring wheel toward the conveyor roll and is compressed by the scoring wheel moving away from the conveyor roll. The compression and extension of the spiraled coiled spring varies the force on the scoring wheel.
In the scoring of glass, in particular thin glass, variation in the force acting on the scoring wheel gives inconsistent scores. If the force acting on the scoring wheel is too high, e.g., above about 10 pounds (4.5 kilograms), the glass surface may be crushed at the score line and if the force acting on the scoring wheel is too low, e.g., below about 3 pounds (1.35 kilograms), the score is not sufficiently deep.
It would be advantageous therefore to have a device available to apply a constant force to a scoring wheel when the scoring wheel oscillates during scoring of a glass sheet or ribbon.